A proper immune response depends on complex interactions between different leukocytes and other cell types and their soluble products, and on an intensive crosstalk among many receptors, which transduce activation signals leading to induction of cell-specific gene programs, differentiation, proliferation, and acquisition of effector functions. A dysregulated immune response can lead to harmful results, the development of autoimmune diseases being a prime example. Aberrant mechanisms that lead to development of inflammation and autoimmunity have been elucidated to a large degree by the genetic manipulation of mice, which led to significant insights into the underlying signaling mechanisms. Thus, genetic alteration of signaling pathways at defined steps can prevent or induce the development of autoimmunity and other immunological diseases. Nevertheless, small scientific meetings that allow intensive interactions and fruitful discussions and, at the same time, bring together scientists working on fundamental aspects of leukocyte signaling pathways and on the clinical implications of these pathways (including relevant disease models) are far and few between. Funds are requested to support an international conference entitled "The 5th International Leukocyte Signal Transduction Workshop" to be held in Crete, Greece, on 6/13-18/09. This is the 5th in a series of similar meetings, which were held since 2000. Previous meetings focused exclusively on basic aspects of signal transduction by leukocyte receptors. The program for the upcoming meeting, with ~100 anticipated participants, will bring together scientists working on fundamental aspects of leukocyte signaling, and those studying animal disease models and clinical implications of these signaling pathways. In addition, several invited talks will present and discuss relevant cutting edge technologies. The invited faculty consists of ~25 internationally known scientists who are recognized experts in relevant research areas. Scientists at the early, formative stage of their career will be given priority in participation and presentation. The Specific Aims of the Workshop are: 1. Extend and continue four previous, highly productive Leukocyte Signal Transduction Workshops. 2. Bring together internationally known scientists, who are experts in leukocyte signal transduction and the disease implications of leukocyte signaling pathways to, e.g., inflammation, autoimmunity, and infectious disease, in order to present and discuss the most up-to-date relevant research. 3. Give scientists at an early stage of their formative career, i.e., postdoctoral research fellows and graduate students, particularly those representing minority groups or coming from developing countries, an opportunity to present and discuss their own ongoing work and to benefit from close, one-on-one interactions with leading scientists, thereby providing an educational experience and a motivation to commit themselves to a clinically relevant scientific research career. The Organizers anticipate that this Workshop will promote sharing of ideas, close interactions and collaborations between scientists working on basic aspects of leukocyte signaling and those studying animal model (or even human) inflammatory and autoimmune diseases. Financial support is requested for a conference entitled "The 5th International Leukocyte Signal Transduction Workshop". This Workshop, the 5th in a series of highly productive meetings initiated in 2000, will be held in Crete, Greece, and will be attended by ~80-100 participants from different countries, including a distinguished faculty of ~22 internationally known speakers, who are all recognized leaders in their respective areas of research. The central focus of the meeting will be the biochemical and molecular mechanisms through which different cell types in the immune system acquire the ability to mount effective immune defense responses against invading microbes, and how aberrations in these pathways can lead to immune system diseases such as autoimmunity and inflammation. The requested support will mostly be used to defray the costs of meeting registration and subsistence costs, with the highest priority being given to trainees representing minority groups or from developing countries.